The USGS Hypsography files contain digital representations of the topographic contours
mapped on the USGS quadrangles. This USGS DLG (Digital Line Graph) data layer contains
a full range of attribute codes, has full topological structuring, and has passed
certain quality control checks. More information regarding USGS DLG data can be
found at <http://edc.usgs.gov/guides/dlg.html>.

Purpose:

These data may be used to construct municipal, regional, or statewide base maps.

The attribute accuracy is estimated to be 98.5 percent. Attribute accuracy was tested
by one or more of the following methods: - manual comparison of the source with hard
copy plots. - symbolized display of the digital line graph on an interactive computer
graphic system. - Selected attributes that could not be visually verified on plots or
on screen, were interactively queried and verified on screen. In addition, U.S.
Geological Survey (USGS) Production System (PROSYS) software tested the attributes
against a master set of valid attributes for the category; it also checked for
selected valid attribute combinations, and for valid attributes relative to topology
and dimensionality. All attribute data conform to the attribute codes current as of
the date of digitizing.

Logical_Consistency_Report:

Topological requirements include: lines must begin and end at nodes, lines must connect
to each other at nodes, lines do not extend through nodes, left and right areas are
defined for each line element and are consistent throughout the file, and the lines
representing the limits of the file (neatline) are free of gaps. The tests of logical
consistency were performed by the USGS PROSYS program. The neatline was generated by
connecting the four corners of the digital file, as established during initialization
of the digital file. All data outside the enclosed region were ignored and all data
crossing these geographically straight lines were clipped at the neatline. Data within
a specified tolerance of the neatline were snapped to the neatline. Neatline
straightening aligned the digitized edges of the digital data with the generated neatline,
that is, with the longitude/latitude lines in geographic coordinates. All internal areas
were tested for closure using PROSYS.

Completeness_Report:

Data completeness reflects the content of the source quadrangle. Features may have been
eliminated or generalized on the source graphic, due to scale and legibility constraints.
For Digital Revision Status = Not revised Reported data completeness reflects the content
of the source quadrangle. Features may have been eliminated or generalized on the source
graphic, due to scale and legibility constraints. For Digital Revision Status = Limited
Update This file has undergone limited update digital revision. The file contains only
(1) those features that are photoidentifiable on monoscopic source, supplemented with
limited ancillary source, and (2) those features, present on the original source
quadrangle, that can not be reliably photoidentified but that are not considered
particularly prone to change. For Digital Revision Status = Standard Update This file has
undergone standard update digital revision. The data completeness of this file meets NMD
standards for feature content.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

For Digital Revision Status = Not revised The Horizontal positional accuracy is
based upon the use of USGS source quadrangles which are compiled to meet National
Map Accuracy Standards (NMAS). NMAS horizontal accuracy requires that at least 90
percent of points tested are within 0.02 inches of the true position. The digital
data are estimated to contain a horizontal positional error of less than or equal
to 0.003 inches standard error in the two component directions relative to the
source quadrangle. Comparison to the graphic source is used as control to assess
digital positional accuracy. Cartographic offsets may be present on the graphic
source, due to scale and legibility constraints. Digital map elements require edge
alignment between data sets. Data along each quadrangle edge are tested against the
data set for the adjacent quadrangle using PROSYS; tests check for positional
accuracy between data sets within a 0.02 inches tolerance. Features with like
dimensionality, and with or without like attribution, that are within the tolerance
are adjusted by moving the feature equally in both data sets. Features outside the
tolerance are not moved. All disconnects are identified by edge matching flags that
document the mismatch. For Digital Revision Status = Limited Update: This file has
undergone limited update digital revision. Accuracy of these digital data meets the
class 1 positional accuracy specifications in the draft United States National
Cartographic Standards for Spatial Accuracy. Digital map elements require edge
alignment between data sets. Data along each quadrangle edge are tested against
the data set for the adjacent quadrangle using PROSYS; tests check for positional
accuracy between data sets within a 0.02 inches tolerance. Features with like
dimensionality, and with or without like attribution, that are within the tolerance
are adjusted by moving the feature equally in both data sets. Features outside
the tolerance are not moved. All disconnects are identified by edge matching flags
that document the mismatch. For Digital Revision Status = Standard Update: This file
has undergone standard update digital revision. Accuracy of these digital data
meets at least the class 2 positional accuracy specification in the draft United
States National Cartographic Standards for Spatial Accuracy. Digital map elements
require edge alignment between data sets. Data along each quadrangle edge are tested
against the data set for the adjacent quadrangle using PROSYS; tests check for
positional accuracy between data sets within a 0.02 inches tolerance. Features with
like dimensionality, and with or without like attribution, that are within the
tolerance are adjusted by moving the feature equally in both data sets. Features
outside the tolerance are not moved. All disconnects are identified by edge matching
flags that document the mismatch.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

For Hypsography, Hydrography and Survey Control and Markers Only: Vertical
positional accuracy is based upon the use of USGS source quadrangles which are
compiled to meet NMAS. NMAS vertical accuracy requires that at least 90 percent of
well defined points tested be within one half contour interval of the correct value.
Comparison to the graphic source is used as control to assess digital positional
accuracy. For Hypsography, Hydrography and Survey Control and Markers Only: For
Digital Revision Status = Limited Update or Standard Update: This file has undergone
digital revision. Accuracy of these digital data meets the class 1 positional
accuracy specifications in the draft United States National Cartographic Standards
for Spatial Accuracy.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator:

US Geological Survey or another mapping agency in
cooperation with USGS

The DLG files provided the basic coordinate information for
the data layer, as well as the fundamental feature codes.

Process_Step:

Process_Description:

The source DLG files were converted into Arc/Info coverages
using the "DLGARC" command. Line topology was constructed
and attributes were appended using basic Arc/Info
utilities. The data were then projected from UTM meters
(zone 18 or 19), NAD27 (or NAD83), to NH State Plane feet,
NAD83. A new field, ELEV, was created and MAJOR/MINOR codes
representing elevation values were migrated to ELEV, converting
from meters to feet if necessary. Coverages were then
converted to shapefile format using the "ARCSHAPE" command.

Source_Used_Citation_Abbreviation: DLG-3

Process_Date: 200805

Source_Produced_Citation_Abbreviation: Version 1

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Organization: Complex Systems Research Center

Contact_Person: GRANIT Database Manager

Contact_Position: GRANIT Database Manager

Contact_Address:

Address_Type: mailing and physical address

Address: Morse Hall, University of New Hampshire

City: Durham

State_or_Province: NH

Postal_Code: 03824

Country: US

Contact_Voice_Telephone: 603-862-1792

Contact_Facsimile_Telephone: 603-862-0188

Contact_Electronic_Mail_Address: granit@unh.edu

Hours_of_Service: 8:30AM-5PM, EST

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Complete Chain

Point_and_Vector_Object_Count: 3766

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: State Plane Coordinate System 1983

State_Plane_Coordinate_System:

SPCS_Zone_Identifier: New Hampshire

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.999967

Longitude_of_Central_Meridian: -71.666667

Latitude_of_Projection_Origin: 42.500000

False_Easting: 984249.999900

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 2.0013 (2.1325 for 25K)

Ordinate_Resolution: 2.0013 (2.1325 for 25K)

Planar_Distance_Units: Feet

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: GRS 80

Semi-major_Axis: 20925604.4720406

Denominator_of_Flattening_Ratio: 298.26

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

DLG3 attribute codes are used to describe the physical and cultural characteristics
of DLG node, line, and area elements. Attribute codes are used to reduce redundant
information, provide enough reference information to support integration with larger
data base, and describe the relationships between cartographic elements. Each DLG
element has one or more attribute codes composed of a three digit major code and a
four-digit minor code. For more information regarding DLG MAJOR/MINOR attribute
codes, please see Part 3 of the Standards for Digital Line Graphs document
(<http://rmmcweb.cr.usgs.gov/nmpstds/acrodocs/dlg-3/3dlg0798.pdf>).

Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Detailed_Description:

Entity_Type:

Entity_Type_Label: hypso201

Entity_Type_Definition: Elevation contours

Entity_Type_Definition_Source: USGS

Attribute:

Attribute_Label: ELEV

Attribute_Definition: Elevation in feet.

Attribute_Definition_Source: Complex Systems Research Center

Attribute_Domain_Values:

Unrepresentable_Domain: Calculated value.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Complex Systems Research Center

Contact_Person: GRANIT Database Manager

Contact_Position: GRANIT Database Manager

Contact_Address:

Address_Type: mailing and physical address

Address: Morse Hall, University of New Hampshire

City: Durham

State_or_Province: NH

Postal_Code: 03824

Country: US

Contact_Voice_Telephone: 603-862-1792

Contact_Facsimile_Telephone: 603-862-0188

Contact_Electronic_Mail_Address: granit@unh.edu

Hours_of_Service: 8:30AM-5PM, EST

Resource_Description: Downloadable Data

Distribution_Liability:

Digital data in NH GRANIT represent the efforts of the
contributing agencies to record information from the cited
source materials. Complex Systems Research Center, under
contract to the NH Office of Energy and Planning, and in
consultation with cooperating agencies, maintains a
continuing program to identify and correct errors in these
data. OEP, CSRC, and the cooperating agencies make no claim
as to the validity or reliability or to any implied uses of
these data.